In a medium bowl, whisk flour, salt, baking powder, and baking soda. In the large bowl of a stand mixer fitted with the paddle attachment (or in a large bowl using a handheld mixer), beat butter, granulated sugar, and brown sugar on medium-high speed until creamy, 2 to 3 minutes. Add eggs, one at a time, beating to blend after each addition. Beat in vanilla.

Reduce mixer speed to low. Add dry ingredients and beat until just combined. Add Oreos and continue to beat until just combined.

Using a ½-cup measuring cup, scoop out dough and roll into balls (about 125 g. per ball). Arrange on 2 parchment-lined baking sheets, spacing 3" to 4" apart. Refrigerate until firm, 30 to 40 minutes.

Place racks in center and upper third of oven; preheat to 375°. Bake cookies, rotating sheets top to bottom and front to back halfway through, until edges are set and turning golden, about 18 minutes. Let cool on sheets 5 minutes, then transfer to wire racks and let cool completely.

In the large bowl of stand mixer fitted with the paddle attachment (or in a large bowl using handheld mixer), beat confectioners’ sugar and butter on medium speed until smooth. Add cream, vanilla, and salt and beat on medium-high speed until incorporated.

Reduce mixer speed to low. Beat in chopped Oreos until just combined.

Using an offset spatula, spread frosting on top of cookies (about 3 tablespoons each). Decorate cookies with a mini Oreo.